function code_draw() {
  var canvas_width = $("#canvas").width();
  var canvas_height = $("#canvas").height();
  var canvas = document.getElementById("canvas");
  var context = canvas.getContext("2d");
  canvas.width = canvas_width;
  canvas.height = canvas_height;
  var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
  var aCode = sCode.split(",");
  var aLength = aCode.length;
  var value = [];
  for (var i = 0; i <= 3; i++) {
    var j = Math.floor(Math.random() * aLength);
    var deg = (Math.random() * 30 * Math.PI) / 180;
    var txt = aCode[j];
    value[i] = txt.toLowerCase();
    var x = 10 + i * 20;
    var y = 20 + Math.random() * 8;
    context.font = "bold 23px 微软雅黑";
    context.translate(x, y);
    context.rotate(deg);
    context.fillStyle = code_randomColor();
    context.fillText(txt, 0, 0);
    context.rotate(-deg);
    context.translate(-x, -y);
  }
  value = value.join("");
  $("#canvas").attr("data-code", value);
  for (var i = 0; i <= 5; i++) {
    context.strokeStyle = code_randomColor();
    context.beginPath();
    context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
    context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
    context.stroke();
  }
  for (var i = 0; i <= 30; i++) {
    context.strokeStyle = code_randomColor();
    context.beginPath();
    var x = Math.random() * canvas_width;
    var y = Math.random() * canvas_height;
    context.moveTo(x, y);
    context.lineTo(x + 1, y + 1);
    context.stroke();
  }
}
function code_randomColor() {
  var r = Math.floor(Math.random() * 256);
  var g = Math.floor(Math.random() * 256);
  var b = Math.floor(Math.random() * 256);
  return "rgb(" + r + "," + g + "," + b + ")";
}

$(function(){
    code_draw();
    // // 点击后刷新验证码
		$("#canvas").on('click', function() {
			code_draw();
    	})
    $(".btn").on('click', function() {
    //     // 将输入的内容转为大写，可通过这步进行大小写验证
        var val = $(".input-val").val().toLowerCase();
    //     // 获取生成验证码值
        var num = $('#canvas').attr('data-code');
        if (val == '') {
            alert('请输入验证码！');
        } else if (val == num) {
            alert('提交成功！');
            $(".input-val").val('');
            draw(show_num);
    
        } else {
            alert('验证码错误！请重新输入！');
            $(".input-val").val('');
            draw(show_num);
        }
    })
})
// module.exports = code_draw;
